#############################################空气质量查询工具
pm25 = input("请输入pm2.5值(输入Q退出)：")
while not pm25 == 'Q':
    pm25 = int(pm25)
    if 0 < pm25 <= 50:
        print("优")
    elif pm25 <= 100:
        print("良")
    elif pm25 <= 150:
        print("轻度污染")
    elif pm25 <= 200:
        print("中度污染")
    elif pm25 <= 300:
        print("重度污染")
    else:
        print("严重污染")
    pm25 = input("请输入pm2.5值(输入Q退出)：")


